C4.1 Confirm or exclude asthma

If airflow limitation is fully or substantially reversible, (FEV1 response to bronchodilator>400 ml), the patient should be treated as for asthma (British Thoracic Society 2008a, Hunter 2002)

Some patients may have coexisting COPD and asthma (Global Initiative for Asthma 2017). Asthma usually runs a more variable course and dates back to a younger age. Atopy is more common and the smoking history is often relatively light (e.g., less than 15 pack-years). Airflow limitation in asthma is substantially, if not com­pletely, reversible, either spontaneously or in response to treatment. By contrast, COPD tends to be progressive, with a late onset of symptoms and a heavier smoking history (usually >15 pack-years) and the airflow limitation is not completely reversible.

COPD patients with features of asthma should receive inhaled corticosteroid therapy (to treat the asthma component), as well as long-acting bronchodilators. LABA monotherapy should be avoided in patients who have a component of asthma (Global Initiative for Asthma 2017).